Hypoxaemia is an important cause of respiratory stimulation and consequent respiratory alkalosis.
The decrease in arterial pCO2 inhibits the rise in ventilation. The hypocapnic inhibition of ventilation (acting via the central chemoreceptors) may leave the patient with an impaired state of tissue oxygen delivery. Adaptation occurs over a few days and the central chemoreceptor inhibition is lessened and ventilation increases.
Correction of hypoxaemia is the most urgent concern and is many times more important than correction of the respiratory alkalosis. Administration of oxygen in sufficient concentrations and sufficient amounts is essential. Attention to other aspects necessary to improve oxygen delivery and minimise tissue oxygen consumption is important.
In some cases this is easy (eg adjustment of ventilator settings, rebreathing via a paper bag with psychogenic hyperventilation) but in some cases it is a slow process.